/* 
 * Copyright 2002-2010 the original author or authors. 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */

package com.zhongan.cglib.demo;

import java.text.NumberFormat;
import java.util.LinkedList;
import java.util.List;

/** 
 * Simple stop watch, allowing for timing of a number of tasks, 
 * exposing total running time and running time for each named task. 
 * 
 * <p>Conceals use of <code>System.currentTimeMillis()</code>, improving the 
 * readability of application code and reducing the likelihood of calculation errors. 
 * 
 * <p>Note that this object is not designed to be thread-safe and does not 
 * use synchronization. 
 * 
 * <p>This class is normally used to verify performance during proof-of-concepts 
 * and in development, rather than as part of production applications. 
 * 
 * @author Rod Johnson 
 * @author Juergen Hoeller 
 * @author Sam Brannen 
 * @since May 2, 2001 
 */
public class StopWatch {

    /** 
     * Identifier of this stop watch. 
     * Handy when we have output from multiple stop watches 
     * and need to distinguish between them in log or console output. 
     */
    private final String id;

    private boolean keepTaskList = true;

    private final List<TaskInfo> taskList = new LinkedList<TaskInfo>();

    /** Start time of the current task */
    private long startTimeMillis;

    /** Is the stop watch currently running? */
    private boolean running;

    /** Name of the current task */
    private String currentTaskName;

    private TaskInfo lastTaskInfo;

    private int taskCount;

    /** Total running time */
    private long totalTimeMillis;

    /** 
     * Construct a new stop watch. Does not start any task. 
     */
    public StopWatch() {
        this.id = "";
    }

    /** 
     * Construct a new stop watch with the given id. 
     * Does not start any task. 
     * @param id identifier for this stop watch. 
     * Handy when we have output from multiple stop watches 
     * and need to distinguish between them. 
     */
    public StopWatch(String id) {
        this.id = id;
    }

    /** 
     * Determine whether the TaskInfo array is built over time. Set this to 
     * "false" when using a StopWatch for millions of intervals, or the task 
     * info structure will consume excessive memory. Default is "true". 
     */
    public void setKeepTaskList(boolean keepTaskList) {
        this.keepTaskList = keepTaskList;
    }

    /** 
     * Start an unnamed task. The results are undefined if {@link #stop()} 
     * or timing methods are called without invoking this method. 
     * @see #stop() 
     */
    public void start() throws IllegalStateException {
        start("");
    }

    /** 
     * Start a named task. The results are undefined if {@link #stop()} 
     * or timing methods are called without invoking this method. 
     * @param taskName the name of the task to start 
     * @see #stop() 
     */
    public void start(String taskName) throws IllegalStateException {
        if (this.running) {
            throw new IllegalStateException("Can't start StopWatch: it's already running");
        }
        this.startTimeMillis = System.currentTimeMillis();
        this.running = true;
        this.currentTaskName = taskName;
    }

    /** 
     * Stop the current task. The results are undefined if timing 
     * methods are called without invoking at least one pair 
     * {@link #start()} / {@link #stop()} methods. 
     * @see #start() 
     */
    public void stop() throws IllegalStateException {
        if (!this.running) {
            throw new IllegalStateException("Can't stop StopWatch: it's not running");
        }
        long lastTime = System.currentTimeMillis() - this.startTimeMillis;
        this.totalTimeMillis += lastTime;
        this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime);
        if (this.keepTaskList) {
            this.taskList.add(lastTaskInfo);
        }
        ++this.taskCount;
        this.running = false;
        this.currentTaskName = null;
    }

    /** 
     * Return whether the stop watch is currently running. 
     */
    public boolean isRunning() {
        return this.running;
    }

    /** 
     * Return the time taken by the last task. 
     */
    public long getLastTaskTimeMillis() throws IllegalStateException {
        if (this.lastTaskInfo == null) {
            throw new IllegalStateException("No tasks run: can't get last task interval");
        }
        return this.lastTaskInfo.getTimeMillis();
    }

    /** 
     * Return the name of the last task. 
     */
    public String getLastTaskName() throws IllegalStateException {
        if (this.lastTaskInfo == null) {
            throw new IllegalStateException("No tasks run: can't get last task name");
        }
        return this.lastTaskInfo.getTaskName();
    }

    /** 
     * Return the last task as a TaskInfo object. 
     */
    public TaskInfo getLastTaskInfo() throws IllegalStateException {
        if (this.lastTaskInfo == null) {
            throw new IllegalStateException("No tasks run: can't get last task info");
        }
        return this.lastTaskInfo;
    }

    /** 
     * Return the total time in milliseconds for all tasks. 
     */
    public long getTotalTimeMillis() {
        return this.totalTimeMillis;
    }

    /** 
     * Return the total time in seconds for all tasks. 
     */
    public double getTotalTimeSeconds() {
        return this.totalTimeMillis / 1000.0;
    }

    /** 
     * Return the number of tasks timed. 
     */
    public int getTaskCount() {
        return this.taskCount;
    }

    /** 
     * Return an array of the data for tasks performed. 
     */
    public TaskInfo[] getTaskInfo() {
        if (!this.keepTaskList) {
            throw new UnsupportedOperationException("Task info is not being kept!");
        }
        return this.taskList.toArray(new TaskInfo[this.taskList.size()]);
    }

    /** 
     * Return a short description of the total running time. 
     */
    public String shortSummary() {
        return "StopWatch '" + this.id + "': running time (millis) = " + getTotalTimeMillis();
    }

    /** 
     * Return a string with a table describing all tasks performed. 
     * For custom reporting, call getTaskInfo() and use the task info directly. 
     */
    public String prettyPrint() {
        StringBuilder sb = new StringBuilder(shortSummary());
        sb.append('\n');
        if (!this.keepTaskList) {
            sb.append("No task info kept");
        } else {
            sb.append("-----------------------------------------\n");
            sb.append("ms     %     Task name\n");
            sb.append("-----------------------------------------\n");
            NumberFormat nf = NumberFormat.getNumberInstance();
            nf.setMinimumIntegerDigits(5);
            nf.setGroupingUsed(false);
            NumberFormat pf = NumberFormat.getPercentInstance();
            pf.setMinimumIntegerDigits(3);
            pf.setGroupingUsed(false);
            for (TaskInfo task : getTaskInfo()) {
                sb.append(nf.format(task.getTimeMillis())).append("  ");
                sb.append(pf.format(task.getTimeSeconds() / getTotalTimeSeconds())).append("  ");
                sb.append(task.getTaskName()).append("\n");
            }
        }
        return sb.toString();
    }

    /** 
     * Return an informative string describing all tasks performed 
     * For custom reporting, call <code>getTaskInfo()</code> and use the task info directly. 
     */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder(shortSummary());
        if (this.keepTaskList) {
            for (TaskInfo task : getTaskInfo()) {
                sb.append("; [").append(task.getTaskName()).append("] took ").append(task.getTimeMillis());
                long percent = Math.round((100.0 * task.getTimeSeconds()) / getTotalTimeSeconds());
                sb.append(" = ").append(percent).append("%");
            }
        } else {
            sb.append("; no task info kept");
        }
        return sb.toString();
    }

    /** 
     * Inner class to hold data about one task executed within the stop watch. 
     */
    public static final class TaskInfo {

        private final String taskName;

        private final long timeMillis;

        TaskInfo(String taskName, long timeMillis) {
            this.taskName = taskName;
            this.timeMillis = timeMillis;
        }

        /** 
         * Return the name of this task. 
         */
        public String getTaskName() {
            return this.taskName;
        }

        /** 
         * Return the time in milliseconds this task took. 
         */
        public long getTimeMillis() {
            return this.timeMillis;
        }

        /** 
         * Return the time in seconds this task took. 
         */
        public double getTimeSeconds() {
            return this.timeMillis / 1000.0;
        }
    }

    /** 
     * test 
     * @throws InterruptedException  
     */
    public static void main(String[] args) throws InterruptedException {
        StopWatch first = new StopWatch("First");
        first.start("A");
        Thread.sleep(200);
        first.stop();
        first.start("B");
        Thread.sleep(200);
        first.stop();
        first.start("C");
        Thread.sleep(120);
        first.stop();
        System.out.println(first.prettyPrint());

    }
}